LAUSR

Noncontact heart rate monitoring that enables the detection of cardiac activity cycles with a normal camera without cutaneous contact has broad application prospects. However, the state-of-the-art approaches lack robustness to the lower illuminance and the varying illuminance. This paper builds an optical noncontact heart rate monitoring framework (lower/vary illumiance PPG, LiPPG) with the aim of improving the robustness of these illuminance situations. In LiPPG, we use the YIQ color space to represent the PPG signal. By applying the Savitzky–Golay filter, we propose a mathematical model, named, multiscale variable-weight Savitsky–Golay combination, to extract signals in the time domain and reduce the disturbance from noise. We test the LiPPG on three scenarios: stationary, facial motion, and varying illuminance, with 18 video clips from 6 participants. The experimental results show that the noncontact heart rate estimation using the LiPPG reduced the errors compared with the gold-standard method of recording from a finger using a pulse oximeter and that it is superior to existing methods.